The present invention relates to a cleaner for inspecting projections, and an inspection apparatus and method for integrated circuits having this cleaner.
More particularly, the cleaner according to the present invention is a cleaner for inspecting projections (e.g., wire conductors such as probe needle or projecting conductors such as bump terminals) used for inspecting the electrical characteristics of integrated circuits and various types of mounted electronic components formed on a semiconductor wafer. The inspection apparatus and method for the integrated circuits according to the present invention are an inspecting apparatus and method having this cleaner, which inspect the electrical characteristics of integrated circuits formed on a semiconductor wafer.
A prober is used as an inspection apparatus for inspecting the electrical characteristics of mounted electronic components, e.g., integrated circuits formed on a semiconductor wafer (to be referred to as a "wafer" hereinafter). This prober is used when inspecting a plurality of IC chips formed on, e.g., a wafer one by one or in a batch. FIG. 3 shows an example of the prober. This prober 10 has a loader unit 11 for conveying wafers W stored in a cassette C, a prober unit 12 for inspecting the wafers W conveyed by a convey mechanism (not shown) disposed in the loader unit 11, a controller 13 for controlling the prober unit 12 and loader unit 11, and a display 14 also serving as a control panel used for operating the controller 13.
A sub chuck (not shown) is disposed in the loader unit 11. The sub chuck prealigns each wafer W with reference to its orientation flat. The wafer W is conveyed to the prober unit 12 by the convey mechanism.
A main chuck 15 for placing the wafer W thereon is arranged in the prober unit 12. The main chuck 15 is movable in the X, Y, Z, and .theta. directions. An alignment mechanism 16 and a probe card 17 are also disposed in the prober unit 12. The alignment mechanism 16 has an alignment bridge 16A and the like for precisely aligning the wafer W, placed on the main chuck 15, with the inspecting position. The probe card 17 has inspecting projections (probe needles) 17A for electrically inspecting the wafer W. The probe card 17 is fixed to the opening portion at the center of a head plate 18 through an insert ring 18A. The head plate 18 can open and close with respect to the top surface of the prober unit 12. A test head 19 is swingably disposed on the prober unit 12. While the test head 19 is flipped open on the prober unit 12, the probe card 17 and a tester (not shown) are electrically connected to each other through the test head 19. A predetermined signal from the tester is supplied to the wafer W on the main chuck 15 through the probe card 17. A plurality of IC chips formed on the wafer W are thus electrically inspected.
When inspecting the wafer W, a drive mechanism moves the main chuck 15 so that the wafer W on the main chuck 15 and the probe needles 17A are aligned with each other. When the main chuck 15 is over-driven upward and the probe needles 17A come into electrical contact with the electrode pads of the IC chips on the wafer W, the IC chips are inspected. The electrode pads of the IC chips are made of, e.g., aluminum. A native oxide film is formed on the surface of the electrode pad of each IC chip. This native oxide film is not preferable to ensure good electrical contact between the probe needle 17A and the electrode pad. Therefore, the probe needle 17A is moved on the electrode pad surface to scrape the native oxide film, thereby ensuring electrical contact between the probe needle 17A and the electrode pad. When inspection of the IC chips is continued, the native oxide film (aluminum oxide or the like) attaches to the probe needle 17A as an attaching substance O, as shown in FIG. 4. The attaching substance O becomes an obstacle in the following inspection.
Hence, a means for cleaning the distal end portions of the probe projections 17A is formed on the main chuck 15. An example of this means will be described with reference to FIG. 5. A mount table 15A is arranged on the side of the main chuck 15. An abrasive plate 20 is attached to the mount table 15A. When the main chuck 15 is vertically moved, the projecting ends of the probe needles 17A come into contact with the abrasive plate 20 and are abraded by it, so that the substance O attaching to them is removed.
In the conventional cleaning method, the probe needles 17A are pressed by the abrasive plate 20 and are abraded by it so that the substance O attaching to their distal ends are removed. However, the entire portions of the distal ends of the probe needles 17A are not always abraded. Sometimes the attaching substance O remains on the distal ends such that it can be easily removed. During inspection, this remaining attaching substance O separates from the distal ends of the probe needles 17A to contaminate the chips. Also, the chippings remaining on the abrasive plate 20 or the abrasive powders of the abrasive plate 20 scatter from the abrasive plate 20 to contaminate the chips. As the feature sizes of chips continue to decrease, the influence of contamination becomes prominent.
When fabricating the probe needle 17A, a burr remains on its needle point. Conventionally, this burr is removed by, e.g., wet etching. This burr removal is a complex operation.
The probe card includes a membrane type probe card. While a large number of bump terminals formed on the membrane of the probe card of this type are in contact with the electrode pads, the electrical characteristics of the chips are inspected. In this case, as inspection is repeated, aluminum oxide or the like attaches to the bump terminals. In the membrane probe card, no means for effectively abrading the bump terminals is available, and it is difficult to remove the substance attaching to the bump terminals.
A flip-chip element has a solder bump on its electrode portion. When this solder bump is fused by heating, the flip-chip element is bonded on the substrate facing down. If an impurity attaches to the solder bump, electrical connection becomes poor. Conventionally, the substance attaching to the solder bump is removed by blasting or the like. However, a measure against scattering of the blasting material during blasting is required.